Determination of the location of mechanical arms and linkages is important. Automation is assisted by mechanisms such as robotic grippers and mechanical arms requires accurate location information. For example, the automated manufacture of a system may require the assembly of parts. These parts must be properly placed in conjunction to one another. To successfully accomplish this function, the position of the part being placed must be known. This criterion is equivalent to the need to know the location of the mechanical linkages controlling the mechanical system which is moving and placing the part. The movement of these mechanical linkages is accomplished using actuators. Hydraulic actuators of choice often consist of a cylinder filled with a hydraulic oil and a movable piston, where the piston is mechanically linked to the movable parts of the mechanical assembly mechanism. Knowledge of the piston's location provides knowledge of the location of the moving parts of the mechanical mechanism. The resolution of the location of the moving parts of the mechanism are in direct relationship to the resolution of the piston location in the hydraulic actuator. Thus, the knowledge of the location of the piston in the cylinder is useful information in determining the location of the moving mechanical parts of mechanisms such as those used for automated assembly, robotics, etc. The precision of location of the actuator piston becomes especially critical for actuators of small size. Actuators of small size are desirable and useful for small mechanical systems, such as, for example, for small robotic grippers.
The method of location of the hydraulic actuator piston is preferably electrical in character in order to easily incorporate electrical controls. Further, a means of accurate piston location where the electrical output has a digital output is also useful.
While precise location knowledge of the activator piston for small systems is a desirable feature, a location determining system which is also applicable to large hydraulic actuators, and which is useful for actuators used in systems other than robotics, is also desirable.
The present invention relates to determining the precise location of a hydraulic actuator position with precision and providing electrical readout which can have digital features suitable for digital electronics use. Analog output is also easily provided.